This is the first year Huntley has offered triathlon as a school sport alongside cricket, tennis and softball.
"It is a popular option with kids," said triathlon coach Gareth Wood.
"Good working with Nicholls Swim Academy and having a 50m local pool. Marton is a great place to learn road biking, the kids have really worked hard."
At the Wanganui championships in team events, Osborne and Thomas were first in the Under 14 girls, while Izzy Williamson and Charlotte Gillespie were third.
The Under 14 mixed team was won by Marshall and Aiden Jones, while Wallace and Blain Quinn were second in the Under 14 boys.